Synthesis of a holographic image velocity filter using the nonlinear photorefractive effect

We demonstrate a technique by which components of an image moving with a given speed and direction may be selectively enhanced. By using the strong grating velocity sensitivity of the nonlinear photorefractive response, we show that a BSO crystal used in a schlieren imaging system may be used as a real-time velocity filter. The velocity selectivity, tunability and resolution constraints of this system are discussed in detail.